既有桥梁体内预应力-增大截面组合加固效果评价

Evaluation of Reinforcement Effect of Existing Bridges Strengthened by Internal Prestress-Enlarged Section Combination

目前现役的箱梁桥病害类型较多,并非单一的因素导致,常用加固方法面临无法满足加固需求的问题,需要针对不同病害情况根据常用加固方法的优缺点互补进行组合加固。由于仅增加箱梁腹板截面对原箱梁截面抗弯惯矩、截面应力和主梁挠度的贡献度较小,本文提出一种箱梁桥体内预应力-增大截面组合加固法,并通过有限元分析加固方法及效果。最不利荷载工况下,采用体内预应力-增大截面组合加固方法加固后,背景桥梁跨中截面底缘拉应力和挠度减小62.74%和34.28%,体内预应力经过新旧腹板粘结界面间传递的损耗率为10.69%,加固效果明显。

At present,there are many types of box girder bridge diseases in active service,which are not caused by a single factor.The common reinforcement methods are unable to meet the reinforcement requirements.Only increasing the web section of box girder has little contribution to the bending inertial moment of original box girder section,section stress and main beam deflection,so a method of internal prestress-enlarged section combination of box girder bridge is proposed,and the reinforcement method and effect are analyzed by finite element method.The results are as follow.Under the most unfavorable load condition,the tensile stress at the bottom edge of the middle section of the background bridge and mid-span deflection decreases by 62.74%and 34.28%.The loss rate of the internal prestress passing through the bonding interface between the old and new web is 10.69%,which shows that the reinforcement effect is obvious.